Peter Robinson has sent his strongest message yet calling for Union flag protests to stop as they are now “synonymous with violence”.

Writing exclusively for Monday’s Belfast Telegraph, the DUP leader branded the violence as “mobocracy” and warned of the deep damage it is causing to unionism.

Mr Robinson’s plea comes after a weekend of fierce rioting engulfed parts of Newtownabbey and east Belfast. The UDA leadership in east Belfast joined calls for a halt to the protests after Saturday’s violence left 29 police officers injured. The worst rioting since the flag row began in early December erupted in east Belfast on Saturday after an estimated 500 people staged a flag protest at Belfast City Hall.

Clashes broke out between loyalists returning from the city centre protest and nationalists living in Short Strand. These were broken up by police, who braved bricks, fireworks and other missiles thrown from the crowd. They responded with water cannon and baton rounds in sustained rioting which went on for several hours.

Mr Robinson said: “In the past it was republicans who claimed that Northern Ireland was a failed political entity. Why on earth would any sensible unionist seek to prove them right through violence, disorder and attacks on the police?”

PSNI Chief Constable Matt Baggott said four of the 29 officers injured on Saturday had to be hospitalised.

Referring to the route taken by many protesters past the Short Strand interface, the PSNI said a preferred route over the Queen’s Bridge had been agreed during “significant engagement with representatives from all communities”. A police statement said trouble began, however, after the “vast majority of the crowd broke away” from this agreed route.

“At this stage many put on masks and covered their faces,” a statement said. “The police came under attack from bricks, stones and missiles.” Mr Baggott paid tribute to his officers. “This was a difficult operation dealing with a large number of people determined to cause disorder and violence.

“My colleagues brought the situation under control with exceptional courage and professionalism. I know the vast majority of people will be grateful for their efforts.” On Sunday night, loyalists staged just one protest, blocking the Albertbridge Road and Castlereagh Street, but there was no trouble.

Speaking in an interview with Radio Ulster, senior UDA figure Jimmy Birch said loyalists “were playing into the hands of Sinn Fein”. He added: “Every time they call a tune, we take to the streets.

“We are wrecking our own areas, we fight with the police, we are burning our own cars and we stop our own people going to work and disrupt our own people's way of life.”

After two days of widespread violence and disruption — coming on the back of 40 days of protests since Belfast City Council decided to fly the Union flag on designated days only — around a thousand people attended a peace rally at City Hall on Sunday.

Snow Patrol lead singer Gary Lightbody on Sunday night tweeted: “Big respect to those who were at the peace rally in Belfast today. Peace and love to all in Northern Ireland. My heart's there always. x.”

Belfast Chamber of Trade and Commerce has now called an urgent meeting with retailers to discuss the damage the protests are causing to the economy.

Mr Robinson and Deputy First Minister Martin McGuinness are due to meet the British and Irish governments this week.